Watch the man who had to race on his own
14 August 2017 Last updated at 13:00 BST
Isaac Makwala was withdrawn from Monday's 200m heats because officials he was ill.
The athlete - who's from Botswana - was stopped from competing in the 400m final by event organisers.
But on Wednesday, he qualified for the 200m with his time running this solo race. He can now run in the final tonight.